core/core_test.go

// Copyright 2017 The Go Authors.  All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package core

import (
	"testing"
)

// loadTest loads a simple core file which resulted from running the
// following program on linux/amd64 with go 1.9.0 (the earliest supported runtime):
// package main
// func main() {
//         _ = *(*int)(nil)
// }
func loadExample(t *testing.T) *Process {
	p, err := Core("testdata/core", "testdata")
	if err != nil {
		t.Fatalf("can't load test core file: %s", err)
	}
	return p
}

// TestMappings makes sure we can find and load some data.
func TestMappings(t *testing.T) {
	p := loadExample(t)
	s, err := p.Symbols()
	if err != nil {
		t.Errorf("can't read symbols: %s\n", err)
	}

	a := s["main.main"]
	m := p.findMapping(a)
	if m == nil {
		t.Errorf("text mapping missing")
	}
	if m.Perm() != Read|Exec {
		t.Errorf("bad code section permissions")
	}
	if opcode := p.ReadUint8(a); opcode != 0x31 {
		// 0x31 = xorl instruction.
		// There's no particular reason why this instruction
		// is first. This just tests that reading code works
		// for our specific test binary.
		t.Errorf("opcode=0x%x, want 0x31", opcode)
	}

	a = s["runtime.class_to_size"]
	m = p.findMapping(a)
	if m == nil {
		t.Errorf("data mapping missing")
	}
	if m.Perm() != Read|Write {
		t.Errorf("bad data section permissions")
	}
	if size := p.ReadUint16(a.Add(2)); size != 8 {
		t.Errorf("class_to_size[1]=%d, want 8", size)
	}
}

// TestConfig checks the configuration accessors.
func TestConfig(t *testing.T) {
	p := loadExample(t)
	if arch := p.Arch(); arch != "amd64" {
		t.Errorf("arch=%s, want amd64", arch)
	}
	if size := p.PtrSize(); size != 8 {
		t.Errorf("ptrSize=%d, want 8", size)
	}
	if log := p.LogPtrSize(); log != 3 {
		t.Errorf("logPtrSize=%d, want 3", log)
	}
	if bo := p.ByteOrder(); bo.String() != "LittleEndian" {
		t.Errorf("got %s, want LittleEndian", bo)
	}
}

// TestThread makes sure we get information about running threads.
func TestThread(t *testing.T) {
	p := loadExample(t)
	syms, err := p.Symbols()
	if err != nil {
		t.Errorf("can't read symbols: %s\n", err)
	}
	raise := syms["runtime.raise"]
	var size int64 = 1 << 30
	for _, a := range syms {
		if a > raise && a.Sub(raise) < size {
			size = a.Sub(raise)
		}
	}
	found := false
	for _, thr := range p.Threads() {
		if thr.PC() >= raise && thr.PC() < raise.Add(size) {
			found = true
		}
	}
	if !found {
		t.Errorf("can't find thread that did runtime.raise")
	}
}